Here's a quick summary of President Obama's latest campaign trip: Six battleground states, 39 hours, quite a few cups of coffee and it's not over yet.

Mr. Obama is about two-thirds of the way through a cross-country barnstorming tour. Right now, he's off to Virginia after holding an event in Florida earlier this morning. Florida's a state, of course, that knows something about razor-close elections. Here's NPR's Scott Horsley.

SCOTT HORSLEY, BYLINE: Florida is the fourth stop on what the president jokingly calls his marathon campaign extravaganza. In the last 24 hours, he's also held rallies in Davenport, Iowa; Las Vegas, Nevada; and before a screaming crowd of 16,000 in Denver, Colorado.

(SOUNDBITE OF RALLY)

PRESIDENT BARACK OBAMA: Are you fired up?

UNIDENTIFIED GROUP: Yeah.

OBAMA: Are you ready to go?

UNIDENTIFIED GROUP: Yeah.

OBAMA: Well, I'm fired up.

HORSLEY: Throughout this trip, the president is drawing contrast between his agenda and Republican rival Mitt Romney's, just as he has for months. But with the election now just 12 days away, Mr. Obama's adding a more direct appeal as he tries to close the sale.

(SOUNDBITE OF RALLY)

OBAMA: I've come to ask you for your vote. I've come to ask you to help me keep moving America forward.

HORSLEY: Polls show a close race nationally, and in almost every one of the battleground states. So neither party can afford to leave any potential votes on the sidelines. That's the message of a new Obama campaign ad inspired by the 2000 presidential race in Florida.

(SOUNDBITE OF POLITICAL ADVERTISEMENT)

UNIDENTIFIED MAN #1: Five hundred and thirty-seven: the number of votes that changed the course of American history.

UNIDENTIFIED MAN #2: Florida is too close to call.

UNIDENTIFIED MAN #1: The difference between what was and what could have been. Make your voice heard. Vote.

OBAMA: I'm Barack Obama...

HORSLEY: That message is especially important for the president, whose strategy depends on expanding the voter base and mobilizing people who don't automatically show up to vote in every election, including young people, African-Americans and Latinos.

From Air Force One yesterday, Mr. Obama telephoned dozens of radio disc jockeys, most of them African-American, urging them to remind their listeners to vote. Later, he appeared on the "Tonight Show," where he told Jay Leno he'll be casting his own vote in Chicago later today.

(SOUNDBITE OF TV SHOW, "THE TONIGHT SHOW")

JAY LENO: Any idea who you're going to be voting for? I don't want to ask just yet.

OBAMA: Well, it's a secret ballot.

LENO: Yeah. It's a secret ballot. Yeah.

OBAMA: Michelle told me she voted for me.

LENO: Oh, that's good.

OBAMA: That was encouraging.

HORSLEY: Early voting is an important part of the Obama strategy, since it makes voting easier for people who might not get to the polls on November 6th.

(SOUNDBITE OF TV SHOW, "THE TONIGHT SHOW")

OBAMA: You know, if you're a factory worker and you've got to punch a clock...

LENO: Right.

OBAMA: ...and, you know, maybe your shift is one where you've got to be there right on time, you've got to take a bus to get to work, it just makes it tougher. So now people can vote, and we want to encourage, obviously, everybody, regardless of who you're voting for, make sure you take advantage of it.

HORSLEY: Denver Mayor Michael Hancock wasted no time after last night's rally trying to get the president's supporters to the polls.

(SOUNDBITE OF SPEECH)

MAYOR MICHAEL HANCOCK: After President Obama is done firing us up, there will be vans ready to go at the same place in which you came in to take you to the nearest polling place. And if you're worried about your car, don't worry about it. They're going to bring you right back here after you vote.

HORSLEY: Colorado Governor John Hickenlooper went a step further, telling the president's supporters not to let up after casting their own votes, but to keep dragging their friends to the polls.

(SOUNDBITE OF SPEECH)

GOVERNOR JOHN HICKENLOOPER: I don't want you to wake up in the morning on the day after the election with a pit in your stomach. I want you to wake up tired, but I want you to be happy, all right - tired because you went out and worked so hard to get these votes and win this election, and you're going to be tired because you stayed up so late celebrating the reelection of Barack Obama.

HORSLEY: The Obama team insists this grind-it-out, vote-by-vote contest is what they always expected, and what they've spent more than a year preparing for. Mr. Obama joked yesterday about pulling an all-nighter on this campaign trip. There could be 13 more long nights ahead.